Organic phosphorosilicon compounds and a process for production thereof

ABSTRACT

1. AN ORGANIC PHOSPHOROSILICON COMPOUND HAVING THE FORMULA:   SI-(O-C(-CH3)2-P(=O)(-O-RI)-O-RII)4   WHEREIN RI AND RII FORM, TAKEN TOGETHER, AN ALKYLENE GROUP HAVING 2 OR 3 CARBON ATOMS OR A HALOGEN-SUBSTITUTED ALKYLENE GROUP HAVING 2 OR 3 CARBON ATOMS, RI AND RII WHEN TAKEN TOGETHER WITH O AND P FORMING A 1,3,2DIOXAPHOSPHOLANE RING.

United States Patent 3,840,577 ORGANIC PHOSPHOROSILICON COMPOUNDS AND A PROCESS FOR PRODUCTION THEREOF Yutaka Kodama and Tsutomu Kodama, Toyama, Masao N akabayashi, N amerikawa, and Shigekazu Komatu, Fuchumachi, Japan, assignors to Toyama Chemical Co., Ltd., Tokyo, Japan No Drawing. Original application Mar. 31, 1970, Ser. No. 24,345, now Patent No. 3,699,188. Divided and this application July 9, 1971, Ser. No. 161,931

Int. Cl. C0711 105/02, 105/04; C07f 7/04 US. Cl. 260448.8 A 9 Claims ABSTRACT OF THE DISCLOSURE Organic phosphorosilicon compounds comprising silicates of a-hydroxyphosphonate prepared by reacting a phosphorous acid triester, a carbonyl compound and a silicon compound containing at least one active chlorine atom. The compounds are effective as flame-retarding agents for inflammable high polymers, particularly synthetic resins, synthetic rubbers and paints.

This Application is a division of Ser. No. 24,345 filed Mar. 31, 1970, which issued as Pat. No. 3,699,188 on Oct. 17, 1972.

This invention relates to a novel organic phosphorosilicon compound. More particularly, this invention relates to a novel silicate of a-hydroxyphosphonate and to a process for producing the same.

Although synthetic resins are widely used in various fields, they have the fatal defect that they are inflammable, by which a further development of the synthetic resins has been prevented. Therefore, many attempts have been made to produce flame-retarding agents for various synthetic resins.

As a result of extensive research thereon, the present inventors have found a novel compound which can impart flame-retarding or self-extinguishing properties to synthetic resins when blended with the latter.

An object of the present invention is to provide a novel, organic phosphorosilicon compound.

Another object of the present invention is to provide a novel silicate of ot-hydroxyphosphonate which can impart flame-retarding or self-extinguishing properties to synthetic resins.

A further object of the present invention is to provide a process for producing a novel silicate of a-hydroxyphosphonate.

Other objects and advantages of the present invention will become apparent to those skilled in the art from the following description.

The present invention provides a novel organic phosphorosilicon compound having the formula:

1 L X OR 21 wherein A is an unsubstituted or halogen-substituted alkyl or alkoxy group having 1 to 4 carbon atoms or an unsubstituted or halogen-substituted alkenyl or alkenoxy group having 2 to 4 carbon atoms or an unsubstituted or halogen-substituted aryl, aryloxy or benzyloxy group having 6 to 8 carbon atoms; X and Y are the same or different groups selected from hydrogen, furyl groups, alkyl groups having 1 to 7 carbon atoms, alkenyl groups having 2 to 7 carbon atoms and aryl groups having 6 to 8 carbon atoms; R and R are unsubstituted or halogen-substituted alkyl groups having 1 to 3 carbon atoms or when taken 3,840,577 Patented Oct. 8, 1974 together form an unsubstituted or substituted alkylene group having 2 to 3 carbon atoms; and n is an integer of 1 to 4.

The novel compound having formula [I] of the present invention is prepared by reacting a phosphorous acid triester having the formula:

0R TO-P wherein R and R are the same as defined above and T is an unsubstituted or halogen-substituted alkyl group having 1 to 3 carbon atoms, a carbonyl group having the formula:

wherein X and Y are the same as defined above and a silicon compound having at least one active chlorine atom and represented by the formula:

wherein A, X, Y, T, R R and n are the same as defined above.

Examples of the phosphorous acid triester used as one of the starting materials in the present invention include trimethyl phosphite, triethyl phosphite, tris (2 chloroethyl) phosphite, tris (2 chloropropyl) phosphite, tris- (2,3 dichloropropyl) phosphite, triphenyl phosphite, 2- methyl 4 chloromethyl 1,3,2-dioxaphospholane, 2-5- chloroethoxy 1,3,2 dioxaphospholane, 2-(2,3-dichloropropoxy)-4-methyl-1,3,2-dioxaphospholane, 2 {3 chloroethoxyl-4-methy1-1,3,2-dioxaphospholane and the like.

The carbonyl compounds having formula [III] used in the present invention include formaldehyde, acetaldehyde, propionaldehyde, acrolein, crotonaldehyde, 2-ethy1hexenal, benzaldehyde, furfural, acetone, methyl ethyl ketone, diethyl ketone, methyl iso-butyl ketone and the like.

The silicon compounds having formula [III] used in the present invention include silicon tetrachloride, methyltrichlorosilane, dimethyldichlorosilane, triethylchlorosilane, trichlorophenylsilane, triphenylchlorosilane, 2- chloroethoxy-trichlorosilane, allyloxy-trichlorosilane, bis- (2 chloroethoxy) dichlorosilane, 2 bromoethoxy-trichlorosilane, methoxy trichlorosilane, dimethoxy dichlorosilane, tris (2,3 dichloropropoxy) chlorosilane, tris-(2-brornoethoxy)-chlorosilane, ethoxy-trichlorosilane, p chlorophenoxytrichlorosilane, dibenzyloxy-di-chlorosilane and the like.

These compounds may be used in any combination to produce an organic phosphorosilicon compound of formula [1] suitable for the purpose of use of the product. The number of the a-hydroxyphosphonate groups present in the compound of formula [I] is determined by the number of the chlorine atoms contained in the starting silicon compound of formula [IV].

The three starting compounds of formulas [II], [III] and [IV] are exothermically reacted upon being mixed to form almost quantitatively, the desired organic phosphorosilicon compound of formula [I]. The starting compounds may be mixed in the following manner: The compound of formula [II] is first mixed with the com pound [IV] and the compound [III] is then added to the resulting mixture, or alternatively, the compound of formula [II] is first mixed with the compound of formula [III] and the compound of formula [IV] is then added to the resulting mixture. In the above reaction, the reactivity of the compound of [II] is weakened with an increase of its molecular weight, and when the compound of formula [III] is a higher aldehyde or ketone, the reaction tends to proceed gradually. When the temperature is not elevated by the reaction, it is preferable to heat the reaction mixture externally. However, in general, the reaction is exothermic, and hence, the reaction is allowed to proceed while cooling the mixture at a temperature of 0 C. to 20 C. and at the end of the reaction, the reaction mixture is preferably heated at a temperature of 50 to 120 C. to complete the reaction. The reaction is, usually, efiected in the absence of a solvent, though an inert organic solvent, such as an aromatic hydrocarbon, for example, benzene, toluene or the like; an aliphatic hydrocarbon, for example, n-hexane; or an aliphatic halohydrocarbon, for instance, methylene chloride, carbon tetrachloride, 1,2-dichl0roethane or the like may be used if necessary. After the completion of the reaction, the chloroalkyl compounds produced as by-products are distilled off at ordinary pressure or under reduced pressure to obtain almost quantitatively the desired organic phosphorosilicon compound.

The organic phosphorosilicon compounds of the present invention are viscous, substantially colorless and transparent liquids, and have been confirmed to have the structure represented by formula [I] by infrared absorption spectrum (peculiar absorption, such as 'y=(P=O), 'y=(POC) and the like, have been confirmed), elementary analysis and reflective index. Examples of the present compound having formula [I] are as shown in Table 1.

TABLEI Refractivc Specific Structural formula index gravity I" 1.480 1.411 Sl-OC|)HP(O)(OCH2OH2C1)2 L CH3 4 1.475 1.396 SiOCHP(O)(OCH2CH2Cl)2 L OHzCHa t CH3 1.479 1.407 OICHQCHZOSiTOCHP(O)(OCHzCHzCl)2] 3 F 1.477 1.403 (C1CHzCH20)2S1-O?HP(O)(OCHgCIIzCl) L CH.

CH 1.472 1.392 (C1CI'IzCH20)3SlO-(?-P(0)(OCIIgCHZCl);

CHs 1.481. 1.389 (CICIIZCHZO)Si O?P(O)(OOHZCIIZC1)Z L CH 3 I 1.492 1.427 ClCH CIIzO-Si0(|3HP(O)(OCH CIIClCHzODz L CH3 3 I" 1.543 CaH5SlOCHP(O)(OCoH5)2 L CHzCH; 3

I'- 1.471 1.385 (MeO)2SlOCHP(O)(OCH2CH2C1)2 I 1.485 (ClCHzCHzO)2Sl-OCHP(O)(OCH CH CDz CH=CHCH3 2 1.495 1.457 Si-OCHP(O)(OCHzCH2C1)Z CH=CH2 4 I 1.481 1.425 (OlCHzClCHCHzO)zSl-O(|JHP(O)(OCHzCHzCDz L CH3 2 CzHs 1. 496 1. 413 (ClCH2CHzO)zSlO(l)P(O)(OCHzCHOlCHzODz L CH3 2 I 1.453 1.271 (O1CHzCHzO)2Sl-OCHP(O)(OCH2CH3)2 L CH2CH3 2 The compound having formula [I] of the present invention can be used as a flame-retarding agent for inflammable polymeric composition, such as synthetic resins, for example, polyurethanes, polymethacrylates, polyesters, polyolefins, polystyrene and the like, coating composition containing these resins (foaming or nonfoaming), fibers, rubbers, waxes and celluloses including ethyl cellulose, nitro-cellulose and acetyl cellulose. Al though the amount of said compound used as a flameretarding agent is not particularly restricted, said compound is preferably added in an amount within a range of 1 to 25% by weight according to the purpose of use of the composition. The compound of formula [I] is particularly effective for polyurethanes and polyesters. For example, it may be mixed in a proportion of 1 to 15% by weight with a polyester resin, and the resulting cured composition has a burning speed which decreases in proportion to increase in amount of the added compound. When 15% by weight of the compound is mixed with a polyester resin, the resin shows a self-extinguishing property.

In general, polymethacrylates, polyurethane and polyolefins, when burnt, are melted and flow. However, when they are mixed with the compound of formula [I], the resulting mixture is not melted and maintains its original form even at high temperatures, and if it is burnt, the burning speed is very low, and the original form remains as is even after burning. However, such characteristics have never been observed in conventional flame-retarding agents comprising an or-ganophosphorous compound, but only in the present flame-retarding agent.

The present invention is further illustrated by the following examples.

EXAMPLE 1 Production of tri{[2-bis2-chloroethyl)-phosphonyl]- 2-propyl}-B-chloroethoxy silane 60.0 g. (0.223 mole) of tris-(2-chloroethyl)-phosphite was mixed with 15.8 g. (0.074 mole) of Z-chloroethoxytrichlorosilane, and into the resulting mixture was dropped 13.0 g. (0.24 mole) of acetone While cooling the mixture with water at a temperature of to C. After the completion of the dropping, the reaction mixture was gradually heated and stirred at 40 C. for 4.5 hrs. to complete the reaction. Slight amounts of unreacted tris- (2-chloroethyl)-phosphite and acetone were thereafter removed from the mixture and then the remaining reaction product was subjected to distillation at 160 C./ 2 mm. to obtain almost quantitatively 66.0 g. of tris{2-[bis-(2- chloroethyl)-phosphonyl]-2-propyl}- 8-chloroethoxy silane (11 1.481; d 1.389) having the following structural formula:

Production of bis-2-chloroethoxy)-silane of diethyl-1-hydroxypropylphosphonate 40.0 g. (0.241 mole) of triethyl phosphite was mixed with 14.0 g. (0.242 mole) of propionaldehyde while cooling with ice water, and into the resulting mixture was dropped 30.0 g. (0.116 mole) of bis-(Z-chloroethoxy) dichlorosilane while cooling the mixture at a temperature of 0 to 5 C. to react them. After the completion of the dropping, the mixture was gradually heated to 55 C., at which temperature the mixture was stirred for min. to

complete the reaction. The reaction product was treated in the same manner as in Example 1 to obtain bis-(2- chloroethoxy)-silane of diethyl-l-hydroxypropyl phosphonate (n 1.455; L1 1.271) having the following formula:

(C1CH CH;O)2Si O CH-P (o) ocrnonoil L CHICHZ 2 Elementary analysis Phos- Chlorine phorus Calculated (percent) 11. 5 10. 04

Found (percent) 12. 0 9. 8

EXAMPLE 3 Production of monomethylsilane of bis-(Z-chloroethyD- 2-hydroxylpropylphosphonate L ta.

Elementary analysis Phos- Chlorine phorus Calculated (percent) 28. 98 12. 65

Found (percent) 29. 04 12. 01

EXAMPLE 4 Production of tetrakis [l-(1,2-propylenephosphonyl)- benzylJ-silicate 186.0 g. (1.01 moles) of Z-fi-chloroethoxy-4-methyl- 1,3,2-dioxaphospholane was reacted with 107.0 g. (1.01 moles) of benzaldehyde, and 42.5 g. (0.25 mole) of silicon tetrachloride was gradually dropped into the resulting reaction mixture at a temperature of 20 to 25 C. After the stop of heat-generation, the reaction mixture was gradually heated to a temperature of to C., at which the mixture was stirred for 1.5 hrs. to complete the reaction. The ethylene chloride produced as by-product was distilled off and the remaining product was concentrated at C./ mm. Hg to remove unreacted materials, thereby obtaining 234.0 g. of a colorless, transparent tetrakis-[1-1,2 propylenephosphonyl)-benzyl] silicate (n 1.520; (1 1.333) having the following structural formula:

O-CH; 'OCHP(0) JGHI. 0-CH C Ha 4 Elementary analysis Phosphorous Percent Calcd. 11.97 Found 11.88

' EXAMPLE 5 Production of 2-propyl-1,2-propylenephosphonyl tri-methylsilane 54.3 g. (0.50 mole) of trimethylchlorosilane was mixed with 118.0 g. (0.50 mole) of 2-(2,3-dichloropropoxy)- .4-methyl-1,2-dioxaphqspholane While cooling them, and

29.0 g. (0.50 mole) of acetone was then dropped thereinto to effect reaction. After the completion of the dropping, the reaction mixture was gradually heated to a temperature of 60 to 65 C., at which stirring was continued for one hour to complete the reaction. The trichloropropane produced as by-product and the excess phospholane were distilled off to obtain 125.0 g. of 2-propyl- 1,2-propylenephosphonyl trimethylsilane having the following structural formula:

CH OCI-h (CHa)aSiO-CP(O i on; O-CH (ilHa Elementary analysis Phosphorus Percent Calcd. 12.25 Found 12.27

EXAMPLE 6 Production of bis-[(3-chloropropylenephosphonyl)- l-allyl]-bis-p-chloroethoxy silane 186.0 g. (1.01 moles) of 2 ethoxy 4 chloromethyl 1,3,2 dioxaphospholane and 124.0 g. (1.01 moles) of bis-(B-chloroethoxy) silane were mixed at a low temperature, and 56.5 g. (1.01 moles) of acrolein was dropped into the resulting mixture while cooling the same at a temperature of 5 to C. to effect reaction. After the completion of the dropping, the reaction mixture was gradually heated to a temperature of 60 to 70 C., at which the reaction mixture was stirred for 1.5 hrs. to complete the reaction. The ethyl chloride produced as byproduct and the slightly excess phospholane were removed to obtain 304.0 g. of bis ['(3 chloropropylene phosphonyD-l-allyl]-bis-,8-chloroethoxy silane having the following structural formula:

Production of tetrakis-[ (3-propylenephosphonyl) -1- ethyl] -silicate In the same manner as in Example 4, 186.0 g. (1.01 moles) of Z-fl-chloroethoxy-4-methyl-1,3,2 dioxaphospholane was mixed with 42.5 g. (1.06 moles) of silicon tetrachloride while being cooled with water, after which 46.6 g. (1.06 moles) of acetaldehyde was added thereto to effect reaction. After the completion of addition, the reaction mixture was gradually heated to a temperature of 80 to 85 C., at which the mixture was stirred for one hour to complete the reaction. The ethylene chloride produced as by-product was thereafter removed under reduced pressure and the remainder was then concentrated at 150 C./4 mm. Hg to remove unreacted materials, whereby 171.5 g. of tetrakis-[(3 propylenephosphonyl)-ethyl]-silicate (n 1.520; d 1.384) having the following structural formula was obtained:

Four equivalents of tris-(2-chloroethyl)-phosphite was mixed with 4 equivalents of acetone, after which 1 equivalent of silicon tetrachloride was dropped into the resulting mixture at a low temperature to effect reaction. The resulting product was a viscous, colorless, transparent compound, which was tetrakis-{[bis-(2-chloroethoxy)- phosphonyl]-2-propyl}-silicate (n 1.485; 11 1.373) having the following structural formula:

Elementary analysis Phosphorus Chlorine Calculated (percent) 11. 44 26. 19 11. 38 26. 20

Found (percent) g. of a polyurethane having the composition shown in Table 2 was mixed with said compound in an amount of 7.5 g., 10.0 g. or 15.0 g. The resulting mixture was stirred at a speed of about 2,000 r.p.m. for 15 min., and then placed in a vessel (20 cm. x 14 cm. x 3 cm.), in which foaming was effected and the foamed product was then allowed to stand at 50 C. for 30 min. The resulting polymerized foamed polyurethane was shaped into a size of 15 cm. x 10 cm. x 2 cm. which was subjected to a test according to Japanese Industrial Standards (1.1.8.) A- 1322-1966 to obtain results as shown in Table 3.

Amounts of compound (grams) Heating time (seconds) Self-extiug'lushing time (seconds) The test sample was heated for 5 or 10 sec. and the self-extinguishing time (burning-continued time) was determined. An additive-free polyurethane ignited in 25 sec. and was not self-extinguished.

EXAMPLE 9 186.0 g. 1.01 moles) of 2-,B-chloroethoxy-4-methyl- 1,3,2-dioxaphospholane, 60.0 g. (1.03 moles) of acetone and 42.5 g. (0.25 mole) of silicon tetrachloride were reacted with each other in the same manner as in Example 8 to obtain tetrakis-[(1,2-propylenephosphonyl)-2- propyl]-silicate (11 1.474, 11 1.332) having the following structural formula:

9 Elementary analysis Phosphorous Percent Calcd. 16.67 'Found 16.61

100 g. of an uncured unsaturated polyester resin having the composition shown in Table 4 was mixed with said compound in an amount of 7.5 g., 10.0 g. or 15.0 g., and the resulting mixture was placed in a vessel of 20 cm. X 14 cm. x 3 cm., in which the mixture was allowed to stand overnight. The mixture was thereafter cured at 80 C. for 2 hrs. The thus cured polyester resin was shaped into a size of 0.2 cm. x 1.0 cm. x 3.0 cm. and then subjected to a burning test, which was carried out as follows: A top of a test sample was contacted with the top of a Bunsen burner flame (7 cm.) to heat the sample for a given time, and its self-extinguishability was examined, whereby a heating time range at which the sample was selfextinguishable was determined. The results obtained were as shown in Table 5, in which for comparison, the result of tris-(2,3-dichloropropyl)-phosphate is also shown.

1 When heating time was shorter than the range, the burnt sample was instantly extinguished, while when heating time was within the range, the burnt sample was extinguished within 20 seconds.

When heating time was within the range, the burnt sample was instantly extinguished.

When an additlve-free sample was heated for more than 4 sec., the sample was not self-extinguished.

EXAMPLE 10 The silicate of hydroxyphosphonate obtained in Example 8 (A) and a tris-{[bis-,B-chloroethoxy)phosphonyl- 2-propyl]}-,B-chloroethoxy silane (11 1.481) (B) obtained by reacting 2-chloroethoxy-trichlorosilane, acetone and tris-(Z-chloroethyl) phosphite in the same manner as in Example 8 were each mixed in an amount of g., 10 g., g. or g. with 100 g. of methyl methacrylate prepolymer, and the resulting mixture was heated at a temperature of 105 to 110 C. for a period of 1 to 1.5 hrs. to form a methacrylate polymer plate. The resulting plate was shaped into a test sample of a thickness of 3 mm. and a width of 10 mm. This sample was subjected to a burning test according to A.S.T.M. D-635 63. That is, a top of the sample was contacted with the top of a Bunsen burner flame to burn the sample and a time until the burning reached a given length of the sample (50 cm.) was determined. The results obtained are as shown in Table 6.

10 What we claim is: 1. An organic phosphorosilicon compound having the wherein R and R form, taken together, an alkylene group having 2 or 3 carbon atoms or a halogen-substituted alkylene group having 2 or 3 carbon atoms, R and R when taken together with O and P forming a 1,3,2- diox-aphospholane ring.

2. Tetrakis 1,2-propylenephosphonyl-2-propyl silicate.

3. Tetrakis 4-chloromethyl-1,2-ethylenephosphonyl-2- propyl silicate.

4. A process for producing an organic phosphorosilicon compound having the formula:

where-in R and R form, taken together, an alkylene group having 2 or 3 atoms or a halogen-substituted alkylene group having 2 or 3 carbon atoms, R and R when taken together with O and P forming a 1,3,2- dioxaphospholane ring, which comprises reacting a phosphorous acid tr-iester having the formula:

wherein R and R are as defined above and T is an alkyl group having 1 to 4 carbon atoms or a halogensubstituted alkyl group having 1 to 4 carbon atoms, with acetone and silicon tetrachloride.

5. A process according to claim 4, wherein the reaction is etfected in an inert organic solvent.

6. A process according to claim 5, wherein the solvent is an aromatic hydrocarbon, an aliphatic hydrocarbon or a halogenated aliphatic hydrocarbon.

7. A process according to claim 6, wherein the aromatic hydrocarbon is benzene or toluene.

8. A process according to claim 4 wherein the reaction is effected at a temperature of 50 to C.

9. A process according to claim 4 wherein the phosphorous acid triester is 2- 8-chloroethoxy-4-methyl-1,3,2- dioxaphospholone.

References Cited UNITED STATES PATENTS 3,113,139 12/1963 Birum et al. 260448.8 R X DANIEL E. WYMAN, Primary Examiner 'P. F. SHAVER, Assistant Examiner U.S. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 5, 40,577 Dated October 8, 197

Inventor(s) Yutaka KOd-ama 1- It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

-- Claims priority, application Japan, May 19, 1969 In the heading to the printed specification, insert th ab v after line 10.

Signed and sealed this 6th day of May 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks USCOMM'DC 60376-PB9 U.5. GOVERNMENY PRINTING OFFICE: 93

F ORM PO-105O (10-69) UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 5 SLPO 577 Dated October 8 97 Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

-- Claims priority, application Japan, May 19, 1969 In the heading to the printed specification, insert th above after line 10.

Signed and sealed this 6th day of May 1975.

(SEAL) Attest C MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks USCOMM-DC 60376-P69 FORM PO-IOSO (10-69) U.S. GOVERNMENT PRINTING OFFICE: 869- 930 

1. AN ORGANIC PHOSPHOROSILICON COMPOUND HAVING THE FORMULA: 